Breast pain and swelling commonly occur 3 to 5 days before menstruation. As everyone's physical condition varies, the severity and duration of breast pain can differ. Clinically, most women experience this discomfort. Generally, the symptoms gradually disappear after the onset of menstruation. This is related to hormonal imbalances involving estrogen before menstruation, or due to the withdrawal of estrogen. If the symptoms are mild, treatment is usually not necessary. It's often sufficient to rest adequately, avoid excessive fatigue, and maintain a good mood and outlook.